基于MC9S12单片机巡航控制系统毕业设计.doc

摘 要 随我国汽车工业的迅速发展，汽车的普及面越来越广，与此同时，人们对汽车的安全性和舒适性要求也越来越高。汽车巡航控制系统可以减轻驾驶员的驾驶疲劳，提高驾车的舒适性，是智能车辆的必备系统，具有重要的研究意义。 本了国内外汽车巡航控制系统的发展状况和发展方向，介绍了基于MC9S12单片机巡航控制系统的构成和基本原理。系统用Freescale l6位单片机MC912DG128作为系统控制处理器。MC9S12单片机巡航控制系统通过车速传感器采集当前的车速信号，与预先设定的速度对比计算偏差，用PID控制节气门转过角度，定的车速，使车辆以一恒定的速度行驶，进而汽车定速巡航控制系统闭环控制方案设计。 设计系统硬件电路， 关键词：巡航控制；PID控制；MC9S12DG128；电子节气门；定速巡航；单片机 ABSTRACT With the development of our country’s automobile industry,Automobiles are more and more popular,at the same time,the security and the comfort of Automobile should be higher and higher.Automobile curise control system（CCS）can ease The tiredness of driver,and improve the comfort of driving,it is the requisite system of the intelligent vehicles,so the study on CCS is of great importance. The automobile CCS development and developing trend of CCS are involved in this design,introduced the structure and fundamental principle of the Automobile cruise control system based on MC9S12 single-chip.The system uses Freescale l6-bit microcontrollers MC9812DG128 as system control processor.Use this type of single-chip feedback to the electronic air damper control,So that throttle and accelerator pedal with the dynamic relationship.On the basis of electronic throttle control,further design cruise control system based on MC9S12 single-chip,through vehicle speed sensor collects vehicle’s running speed signal,compares with beforehand enactment speed and computes between the speed deviations,using PID control,adjust the angle of turn throttle,to change the speed to set the speed,make the vehicle with a constant speed,to realize the car cruise control system of closed-loop control of the scheme design. Based on the design of cruise control system,design hardware circuit of system,and building cruise control simulation platform in laboratory, the design of cruise control system for experiment,in order to verify the feasibility and stability of the designed system. Key words：urise control；PID control；MC9S12DG128；lectronic air